v2.4.0.6

COMMITMENTS AND CONTINGENCIES Narrative (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2012
Loss Contingencies [Line Items] |
Loss Contingency Accrual, at Carrying Value | $ 43.6
Grace Energy Corporation Matter [Member] |
Loss Contingencies [Line Items] |
Court Judgment, Remediation Costs Not Recoverable by Plaintiff | 3.5
Court Judgment, Attorney Costs Awarded to Plaintiff | 1.8
Deptartment of Justice Estimated Remediation Expenses | 71.9
Loss Contingencies, Estimated Settlement Payment | $ 11.7

X
- Definition Attorney costs awarded to plaintiff, per a court judgment + References No definition available. + Details
Name: | ns_CourtJudgmentAttorneyCostsAwardedToPlaintiff
Namespace Prefix: | ns_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Remediation costs not recoverable by plaintiff, per a court judgment. + References No definition available. + Details
Name: | ns_CourtJudgmentRemediationCostsNotRecoverableByPlaintiff
Namespace Prefix: | ns_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Department of Justice past and future estimated remediation expenses. + References No definition available. + Details
Name: | ns_DeptartmentOfJusticeEstimatedRemediationExpenses
Namespace Prefix: | ns_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The estimated amount an entity will pay in a settlement agreement to resolve the legal matter. + References No definition available. + Details
Name: | ns_LossContingenciesEstimatedSettlementPayment
Namespace Prefix: | ns_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying amount as of the balance sheet date of the combined total of loss contingency liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 5 -Paragraph 9, 10, 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant